Sizing to fit cylinder chambers

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Makeminea45

Bearcat
Joined
Nov 5, 2009
Messages
6
Just looking for a few opinions on this subject. My 45 Colt Bisley has a bore that measures .451 I have slugged it twice to be sure. The chambers mouths measure .4545 with 2 that go .455. I can push unsized bullits at .454 through the cylinders with very little pressure. I tried some RCBS 270 SAA that I cast and the results where not that great. I had to size them at .452 because that's the sizer I had on hand at the time. I was able to lube some without sizing but have not tried any yet. I also have a .454 sizer on the way. With the bullit sized this much over bore would I run into any problems with pressure spikes or anything else I should know? I would like to work up 2 loads for this gun. One around the 1000 fps mark and the other in the 1250 fps range. I've chrono'd some of the loads I have shot and I am within this range. Thanks.
 

J Miller

Blackhawk
Joined
Sep 30, 2000
Messages
977
Location
Not in IL anymore ... :)
Makeminea45":3srt3isd said:
Just looking for a few opinions on this subject. My 45 Colt Bisley has a bore that measures .451 I have slugged it twice to be sure. The chambers mouths measure .4545 with 2 that go .455. I can push unsized bullits at .454 through the cylinders with very little pressure. I tried some RCBS 270 SAA that I cast and the results where not that great. I had to size them at .452 because that's the sizer I had on hand at the time. I was able to lube some without sizing but have not tried any yet. I also have a .454 sizer on the way. With the bullit sized this much over bore would I run into any problems with pressure spikes or anything else I should know? I would like to work up 2 loads for this gun. One around the 1000 fps mark and the other in the 1250 fps range. I've chrono'd some of the loads I have shot and I am within this range. Thanks.

You won't run into any pressure problems. I have a S&W 25-5 with .457" throats and a .4515" bore. I have bought hard cast 265 gr Keith SWCs from Beartooth Bullets sized to .457" and shot them with no problems at all from that pistol. As a matter of fact the leading problem ceased and the accuracy improved dramatically. Since then I've been shooting my own Lyman 454424 bullets at .455" from it due to the fact I can't find a .457" sizer. They work OK.

As Ale-8(1) said, work up slowly to your desired loads.

Joe
 
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